Recently, a secondary battery, which can be charged and discharged, has been widely used as an energy source for wireless mobile devices. Also, the secondary battery has attracted considerable attention as a power source for electric vehicles (EV) and hybrid electric vehicles (HEV), which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel.
Small-sized mobile devices use one or several battery cells for each device. On the other hand, middle- or large-sized devices, such as vehicles, use a middle- or large-sized battery module having a plurality of battery cells electrically connected with each other because high output and large capacity are necessary for the middle- or large-sized devices.
Preferably, the middle- or large-sized battery module is manufactured with small size and small weight if possible. For this reason, a prismatic battery or a pouch-shaped battery, which can be stacked with high integration and has a small weight to capacity ratio, is usually used as a battery cell of the middle- or large-sized battery module. Especially, much interest is currently generated in the pouch-shaped battery, which uses an aluminum laminate sheet as a sheathing member, because the weight of the pouch-shaped battery is small, the manufacturing costs of the pouch-shaped battery are low, and it is easy to modify the shape of the pouch-shaped battery.
For the middle- or large-sized battery module to provide output and capacity required by a predetermined apparatus or device, it is necessary for the middle- or large-sized battery module to be constructed in a structure in which a plurality of battery cells are electrically connected in series with each other, and the battery cells are stable against an external force.
Consequently, when a middle- or large-sized battery module is constructed using a plurality of battery cells, a plurality of members for mechanical coupling and electrical connection between the battery cells are generally needed, and, as a result, a process for assembling the mechanical coupling and electrical connection members is very complicated. Furthermore, there is needed a space for coupling, welding, or soldering the mechanical coupling and electrical connection members, with the result that the total size of the system is increased. The increase in size of the system is not preferred in the aspect of the spatial limit of an apparatus or device in which the middle- or large-sized battery module is mounted. Furthermore, the middle- or large-sized battery module must be constructed in a more compact structure in order that the middle- or large-sized battery module is effectively mounted in a limited inner space, such as a vehicle.
In addition, a power switching module used to manufacture the middle- or large-sized battery module includes a plurality of control elements for withdrawing electricity of the battery module to the outside. As a result, the structure of the power switching module is very complicated, and it is difficult to assembly the power switching module.
Consequently, there is a high necessity for a power switching module, used in a battery module assembly, which has an optimum arrangement structure suitable to a specific structure of the battery module assembly such that the power switching module can be electrically or mechanically coupled to the battery module assembly while the power switching module is structurally stable.